Flexible stay-bolt for boilers.



F. LANDGRAF'. FLEXIBLE STAY BOLT FOR BOILERS.

' A'PPUCATION FILED FEB. 21.19H-

Lfifi, 1. mm Feb. 19, 1918.

1 7 1- 1 w i I,

I Attorneys if [NVENTOR Q7/- I V M funrrn ermine "Parana FREDERICKLANDGEAF, OF BRIDGEVILLE, PENNSYLVANIA, ASSIGNOR IO FLANNERY BOLTCOFIPANY, OF BRIDGE UILLE, PENNSYLVANIA.

FLEXIBLE'STAY-BOLT FOR BOILERS.

Application filed February 27, 1917.

To all whom it may concern:

Be it known that I, FREDERICK LANDGRAF, a citizen of the United States,and a resident of Bridgeville, in the county of Allegheny and State ofPennsylvania, have invented certain new and useful Improvements inFlexible Stay-Bolts for Boilers; and I do hereby declare the followingto be a full, clear, and exact description of the invention, such aswill enable others skilled in the art to which itappertains to make anduse the same.

' This invention relates to the manufacture of flexible staybolts forboilers, and more particularly to such as are made from tubularbars,-one object of my present invention being to provide a simple andefficient method of forming an integral spherical head at the outer endof a tubular iron body,

without contracting or interfering with the continuity of the bore whichforms the telltale hole of the bolt from the inner end to the headed endof the bolt, and so that the outer end of said bore or tell-tale holeshall terminate within and be closed by said integral head.

l/Vith this object in view, the invention consists in certain novelfeatures or steps in the method of making a flexible staybolt, ashereinafter set forth and pointed out in the claims.

In the accompanying drawings, Figure 1 is a view of a tubular bar fromwhich the bolt is made; Fig. 2 is a View showing the 'rst step in themethod of forming the head; Fig. 3 is a view illustrating the next stepwith the integral spherical head formed on the bar; Fig. 4 is a viewillustrating the bolt with the completely formed head with the here ortell-tale hole extending continuously from the inner end of the bolt tothe headed outer end and terminating within the head, and Fig. 5 is aView illustrating the manner in which the outer end of the bore may beclosed prior to the forging of the head.

1 represents a tubular bar of iron, the bore 2 of which constitutes thetelltale hole of the finished bolt.

In proceeding to form the spherical or partly spherical head 3 on theouter end of the bolt, the end of the barwill be suitably heated and amandrel 4: is inserted into the bore 2. The heating of the bar may beper formed either before or after the insertion Specification of LettersPatent.

Patented Feb. 19, 1%18.

Serial No. 151,251.

of the mandrel. The mandrel may be slightly tapering at its forward end,as indicated at 5, and if desired the mandrel may be coated withgraphite to permit its ready removal after the head shall have beenforged on the bar or bolt body. The mandrel will be passed through thebore 2 until its forward end shall occupy a position therein which willbe within the head subsequently forged. The tubular bar with the mandreltherein as above explained, will next be subjected to the action offorging dies 6, whereby the metal at the outer end of the bar will beupset or forged to form the spherical or partly spherical head 3. Themandrel 4 may then be withdrawn as shown in Fig. 4 and the bolt removedfrom the forging dies. and the headed bolt will have a tell-tale holeextending continuously from its inner end to the headed end and willterminate within and be permanently closed by the integral head.

The bore may be closed at its outer end in any suitable manner beforeforging the head. Thus, a plug 7 may be secured in said outer end of thebore, as shown in Fig. 5, and then the head may be forged as inclicatedby dotted lines, and during such forging operation, the plug will becomewelded in the head.

Having fully described my invention what I claim as new and desire tosecure by Letters-Patent, is

1. The herein described method of making a staybolt, consisting ininserting a mandrel partially through a tubular bar, forging a head onsaid tubular bar and then withdrawing the mandrel, leaving the borecontinuous from the inner end of the bolt and extending into the headedend and closed at the outer end of the bolt within the forged headthereon.

2. The herein described method of making a staybolt, consisting ininserting a mandrel partially through a tubular bar, forging a head onsaid bar over and about the forward end of the mandrel, and then withdrawing the mandrel, leaving the bore of the bolt continuous from theinner end of the bolt to a point within the forged head at the outer endof the bolt.

3. The herein described method of making a staybolt consisting ininserting a mandrel partially through a tubular bar closed at oneeendythen "forging a headxon flghe closed In itestimo ny whereof, I havesigned this end of said tubular bar and then withdrawv, pecification inthe presence of two subscribing the mandrel leaving the bore continuous111g Witnesses.

, from theinnei end of the bolt and exte'nd- FREDERICK "LANDG'RA'F. inginto the headed end, and closed at fihe Witnesses:

outer end of the bolt in the forged head H. VSCHADEL,

thereon. V. E. SKELLEY.

'cbples of this patent may be obtained forrfive cents each, byaddressing the Commissioner of iPatents,

washingtomlkc. I

